Food products and systems and methods of making same

ABSTRACT

Food products and systems and methods for their production involve microfiltration (“MF”) of fluid skim to form a MF retentate, combining the MF retentate with cream and subjecting the combination to ultrafiltration (“UF”) to form a UF retentate. Prior to UF, the composition is formed of non-acidified components. Following UF, the UF retentate is acidified and forms a food product including a high solids content. The solids content may be further increased using evaporation. The resulting cheese or cheese base contains a lower whey protein ratio in a fat:casein:whey protein ratio compared to systems and methods that do not employ MF.

CROSS-REFERENCES TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/601,865 filed Jan. 21, 2015, issued as U.S. Pat. No. 9,826,751 onNov. 28, 2017, which claims priority to U.S. Provisional Application No.61/929,844 filed Jan. 21, 2014, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure generally relates to food products, such ascheese or cheese base products, and systems and methods for theirmanufacture.

BACKGROUND

In prior cheese making processes, whole milk was typically subjected tonatural cheese making processes and subsequently used as a component formaking process cheese products. In other prior approaches, whole milkwith added cream was concentrated using ultrafiltration and culturesand/or enzymes were added, followed by adjusting the moisture content.Use of ultrafiltration without microfiltration resulted in retention ofwhey proteins, which can contribute to melt restriction and undesirablesoftening of process cheese products. In further prior approaches,cheese making processes involve acidification prior to ultrafiltration.However, the production of acidified precursors provide challenges tofiltration and to controlling the pH of the final product.

SUMMARY

Implementations are directed to food products, such as cheese and cheesebase products, and systems and methods for their production.

In one exemplary implementation, a method of forming a food productinvolves separation of whole milk into cream and skim milk followed bymicrofiltration (“MF”) of the skim milk to form a MF retentate. Creammay then be added to the MF retentate, and the cream and MF retentatemay be subjected to ultrafiltration (“UF”) to form a UF retentate.Acidification of the UF retentate, may result in the food product.

In some implementations the MF retentate, the UF retentate or both maybe subjected to diafiltration (“DF”).

In some implementations, the cream from the whole milk in which the skimmilk is derived is used in the UF step of the UF retentate.

In some implementations, the UF retentate may be subjected to blending,homogenization, evaporation, cooking and/or other processing steps.

Implementations provide methods for the production of a food productthat involve separating whole milk into cream and skim milk; subjectingthe separated skim milk to MF to remove at least a portion of wheyprotein from the skim milk to form a skim milk MF retentate; combiningthe separated cream with the skim milk MF retentate; subjecting thecombined cream and skim milk MF retentate to UF to remove moisture andincrease total solids thereby forming a UF retentate; and acidifying theUF retentate to form the food product. Prior to the step of acidifying,the cream, skim milk, skim milk MF retentate and UF retentate arenon-acidified.

In some variations, the skim milk MF retentate may be subjected todiafiltration prior to the step of combining the separated cream withthe skim milk MF retentate, where diafiltration removes lactose andwhey/serum protein from the skim milk MF retentate. In addition oralternatively, the UF retentate may be subjected to diafiltration priorto the acidifying step, where diafiltration removes lactose from the UFretentate. In addition or alternatively, the acidified UF retentate maybe blended with one or more additives such as dairy powders, milk fat,cultures and/or water, alone or in combination with salt and/or lacticacid. The food product may be cooked, and emulsifiers may be added tothe food product during cooking. In addition or alternatively, the stepof subjecting the separated skim milk to MF may involve MF of theseparated skim milk that is not fat corrected, and the MF retentate maybe combined with cream that has not been further processed and thecombination subjected to UF. In addition or alternatively, the foodproduct may be provided to one or more of a stuffer, a filler or a metaldetector.

Methods for the production of a food product may involve subjecting skimmilk to MF to remove at least a portion of whey protein from the skimmilk to form a skim milk MF retentate; combining the cream with the skimmilk MF retentate; subjecting the combined cream and skim milk MFretentate to UF to remove moisture and increase total solids therebyforming a UF retentate, where the UF retentate contains at least about 1wt % salt; and maintaining a viscosity of the UF retentate below 1000 cPfor at least 8 hours.

In some variations, the step of maintaining a viscosity of the UFretentate below 1000 cP is by circulating the UF retentate using one ormore of pumping or sweeping. In addition or alternatively, after thestep of maintaining, the viscosity of the UF retentate is adjusted to aselected viscosity, which may be through homogenization. In addition oralternatively, a portion of the MF retentate may be reserved prior tothe step of combining; and the reserved portion of the MF retentateadded to the UF retentate to form, thereby increasing moisture andprotein in the UF retentate. In addition or alternatively, prior to thestep of subjecting to UF, the combination of the cream and the skim milkMF retentate is non-acidified. In addition or alternatively, furthercomprising, prior to the step of combining, the MF retentate may besubjected to a second MF at a second temperature different from thefirst such that beta casein is removed, or the MF retentate is cooled toa temperature of about 40° F. to 60° F. and subjected to MF.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1, 2 a, 2 b, 3, 4 a, 4 b and 5 illustrate exemplary food productproduction methods according to implementations of the presentdisclosure.

FIG. 6 is a graph illustrating UF retentate viscosity results during apump test over 48 hours at 140° F.

FIG. 7 is a graph illustrating UF retentate viscosity results duringsweep testing over about 42 hours at 140° F.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Overview:

Natural cheese, process cheese products, concentrates, and other foodproducts may be produced according to the present disclosure. Theprocesses may involve separation, microfiltration, and ultrafiltrationof milk to form a concentrate, as well as acidification, shear, andevaporation of the milk concentrate. Filtration steps may take placeprior to acidification. Processes may result in a food product such as aconcentrate, a cheese and/or a cheese base with a high solids content,which may be produced in continuous or batch production processes with areduced processing time, for instance, compared to the processing timesof traditional cheese or process cheese processing times. Furthermore,the properties of the food product can be adjusted by in-line additionof components such as additives (e.g., salt, acidifiers (e.g., lacticacid), dairy powders, milk fat, water, protein (e.g., microfiltrationretentate), sugar, cultures, enzymes and/or emulsifiers (e.g.,citrate-based salts such as sodium citrate and potassium citrate and/orphosphate-based salts such as calcium phosphate and monosodiumphosphate) and adjusting operation parameters.

According to implementations of the present disclosure, microfiltration(“MF”) involves a physical separation process of serum protein (e.g.,whey protein) from fluid skim, and it has been discovered that removalof this protein may provide food products such as natural and processcheeses with better texture and flavor compared to prior approaches dueto these products containing a lower level of whey proteins obtained byremoval through MF as opposed to denatured whey protein being present,or whey protein that inherently displaces casein protein, or both,remaining in the end product. To illustrate, in prior approaches, somealternate cheese making processes used ultrafiltration (“UF”) as afiltration method in order to concentrate milk, and this is a processthat retains all proteins, including whey proteins, as well as fat.Consequently, the ratio among fat:casein:whey protein is the same asthat in milk. According to the present disclosure, by using MF, aportion of the serum proteins (or whey) are removed in the permeatestream, and with less serum proteins (e.g., whey), subsequent UF of theMF retentate and cream results in a UF retentate with a lower wheyprotein ratio in fat:casein:whey protein, which may improve producttexture and flavor. In addition, the whey protein may be collected inthe MF permeate in a more native state with improved functionalproperties. In particular, traditionally, whey proteins are obtained bya cheese-whey process and whey proteins are less native due topH/culture treatment. Additionally residual fat and oxidative productscan remain in the whey via the cheese-whey process. Consequently, theseparation of serum protein in their native form provides benefits inthat the serum protein in the MF permeate has improved functionalproperties, such as water-binding, cleaner flavor and solubility.

DETAILED DESCRIPTION OF THE FIGURES

As illustrated in the system 100 of FIG. 1, cream is separated fromwhole milk in a separator 110 and the skim milk is fed to a MF unit forinitial concentration. The MF of the fluid skim may remove serumproteins, lactose, and minerals in a serum protein enriched/fractionatedMF permeate stream. The initial concentrating of the fluid skim mayadditionally involve one or more diafiltration (“DF”) steps based on thedesired level of extraction of the serum protein and lactose. Forinstance, a portion of the serum protein and lactose contained in theskim milk or MF retentate may be washed out of solution while retainingother components of the skim milk or MF retentate. The number of DFsteps may be dependent upon the desired properties of the MF retentateand the final product. The retentate of MF and optional DF steps mayinclude fat, and a portion of the initial protein, lactose, mineral andmoisture content.

The retentate from MF and the optional DF steps (“MF/DF retentate”) 120may be combined with cream, and the combination of the MF/DF retentateand cream may be concentrated by ultrafiltration (“UF”) to reach a hightotal solids content. UF may remove moisture and lactose from thecomposition as permeate. Additional DF steps may remove lactose. Theretentate stream of the UF and optional DF steps (“UF/DF retentate”) 130may be the MF retentate and cream as a secondary retentate, and may becomprised of fat, and a portion of the initial protein, lactose, mineraland moisture content.

The UF/DF retentate may be blended with additives such as salt andlactic acid to adjust, for example, texture and pH using one or moreblending tanks 140. The blended UF/DF retentate may be homogenizedthrough inline shearing, such as using a shear pump 150. The optionallyblended and homogenized UF/DF retentate may be fed to an evaporator 160such as a wiped film evaporator to adjust the moisture content of theretentate and form a food product (e.g., cheese/cheese base).Thereafter, optional additives such as cultures or enzymes may be addedto the food product and filled into barrels or boxes using a fillingstation 170 and/or a barrel filling system 180. In addition oralternatively, additives may be introduced prior to feeding the UF/DFretentate to the evaporator 160, and for instance, may be introduced inliquid or powder form.

According to another exemplary embodiment, a food product may beproduced according to the system 200 of FIG. 2a . Aspects of system 200that are the same as system 100 include numbering corresponding toFIG. 1. According to this embodiment, a high total solids stream mayresult from concentration steps of MF and UF, with optional DF steps foreach of MF and UF according to steps 110-130. As shown in FIG. 2a , saltand lactic acid may be added to the UF/DF retentate (e.g., the MFretentate-cream secondary retentate) in one or more blending tanks 140.Other additives may additionally or alternatively be added to theblending tanks 140. For instance, cultures may be added to the UF/DFretentate for culturing the composition prior to further processing.After blending, the UF/DF retentate may be homogenized within a shearpump 150. After homogenization, the UF/DF retentate may be subjected toevaporation 160 for further concentration through moisture removal. Themoisture-adjusted UF/DF retentate may form a concentrate that may beblended in a blender 210 with various additives such as dairy powders,milk fat, cultures, emulsifiers (e.g., citrate-based salts such assodium citrate and potassium citrate) and water and be provided to acooker 220 where additives such as emulsifiers may be added, and thecooked food product may be sent to a filler 230 for packaging. In thisembodiment, a straight-to-blender cooking process may eliminate the needto fill the mixture into barrels and hold prior to the furtherprocessing such as cooking.

FIG. 2b provides another exemplary embodiment of a system 250 forproduction of a food product. The UF/DF retentate may be produced with ahigh total solid stream as described in connection with the system andoperations of steps 110-130 in FIG. 1, and the UF/DF retentate may beconcentrated using an evaporator 160 to form a food product. Accordingto FIG. 2b , the product from the evaporator 160 may be blended in ablender 210 as in FIG. 2a , but in this embodiment, the UF/DF retentateis blended additionally with salt and lactic acid, in combination withvarious other additives (e.g., dairy powders, milk fat, emulsifiersand/or water) described in connection with FIG. 2a , and the mixture maybe sent to a cooker 220 where additives such as emulsifying salts may beadded to the mixture. Cooking the mixture may form a food product, whichmay be sent to a filler 230 for packaging. In addition to eliminatingthe need to fill the product (e.g., cheese base) into barrels and holdprior to further processing, the embodiment of FIG. 2b may eliminate theneed for blending tanks 140 for blending the salt and lactic acid priorto evaporation.

FIG. 3 illustrates yet another implementation for producing a foodproduct according to the present disclosure. In system 300 of FIG. 3,and similar to FIG. 1, a high total solid stream of a UF/DF retentatemay be produced and then provided to one or more blending tanks wherecomponents such as salt, lactic acid and other additives may be blendedwith the UF/DF retentate according to steps 110-140. The mixture may behomogenized to form a homogenous food product using a shear pump 150.The food product may be filled into barrels or boxes using a barrelfilling station 180 and cooled for further processing or cured and thencooled prior to further processing. For example, curing may provideoptional cultures or enzymes a suitable time/temperature combination toyield enhanced flavor and/or texture characteristics. The embodiment ofFIG. 3 may eliminate the need for moisture adjustment throughevaporation using an evaporator, such as evaporator 160.

FIG. 4a is another approach to producing a food product according to thepresent disclosure. In the system 400 of FIG. 4a , a UF/DF retentate maybe provided according to steps 110-130, and the UF/DF retentate may beblended (e.g., via blending tank(s) 140) and sheared (e.g., via shearpump 150) as described in connection with FIG. 1. Blending in one ormore blending tanks 140 may involve mixing the UF/DF retentate withadditives such as salt and/or lactic acid, and the blended UF/DFretentate may be homogenized. The homogenized UF/DF retentate may betransported to a blender 210 where it may be mixed with additives suchas dairy powder, milk fat, emulsifiers and water, and the combinedmixture may be sent to a cooker 220, where additives such as emulsifyingsalts may be added and the mixture then converted to a process foodproduct (e.g., process cheese). The process food product may be sent toa filler 230 for packaging. In addition to eliminating the need formoisture adjustment through evaporation as in the method of FIG. 3, theembodiment of FIG. 4a may eliminate the need to fill the mixture intobarrels and hold prior to the further processing such as cooking.

FIG. 4b is yet another approach to producing a food product according tothe present disclosure. In system 450 of FIG. 4b , a UF/DF retentate maybe provided according to the method described in connection with system100 of FIG. 1, and the UF/DF retentate may be blended in a blender 210with components such as salt, lactic acid, emulsifiers and otheradditives. This combined mixture may then be sent to a cooker 220 whereemulsifying salts may be added to the mixture to produce a process foodproduct, which may be sent to a filler 230 for packaging. In FIG. 4b , asubstantial portion of the additives used in forming the food productmay be added to the UF/DF retentate in the blender 210. This may removethe need for use of blending tanks 140 and shear pumps 150. However, insome implementations, homogenization may take place in any of a blender210, an optional blending tank 140 or shear pump 150. In addition oralternatively, a blending tank 140 or a shear pump 150 may replace theblender 210 in the embodiment of FIG. 4 b.

In the foregoing embodiments, the compositions leading to the formationof the UF/DF retentate are non-acidified compositions, e.g.,non-acidified cream, skim milk, MF retentate, DF retentate and UFretentate. It has been discovered that forming the UF/DF retentate witha high solids content prior to acidification prevents damaging thefunctionality of MF permeate used to develop certain food products. Inaddition, forming the UF/DF retentate without acidified components doesnot change the pH of UF permeate, consequently preventing damage of itsfunctionality to develop certain food products via eliminatingaltogether the acidulants entering these product streams. In addition,forming the UF/DF retentate without acidified components preventsmembrane fouling that might otherwise occur due to formation of a “saltbridge” between soluble calcium, released by lowering pH, and membranes.Further, the non-acidified UF/DF retentate prevents membrane fouling dueto the precipitation of protein and formation of curd, which occurs atlower pH. Non-acidified compositions resulting in the UF/DF retentateavoids the change of ratio of calcium in soluble form vs. colloidalform, which affects the texture of food products. Further still, thisallows an accurate adjustment of pH levels in the final food products.

Furthermore, in the foregoing embodiments, the composition subjected toMF is fluid skim, which is the product of separating cream from wholemilk. The fluid skim may not be processed further prior to MF. Forexample, the fluid skim may not be fat corrected prior to MF. The MFretentate may be fluid skim with a portion of the serum protein, lactoseand minerals removed.

Moreover, the MF retentate may be combined with the cream derived fromthe whole milk from which the fluid skim was derived, and the cream maynot be subjected to further processing between the separation and UFsteps. Thus, the composition subjected to UF may be fluid skim with aportion of the serum protein removed and cream. Lactose from the fluidskim may additionally be removed in the optional DF steps associatedwith MF, e.g., preceding optional DF steps associated with UF. Becausecream retains substantially all of the fat and a portion of the proteinfrom the whole milk and is added to the MF retentate containing aportion of its original protein, the resulting product contains a lowerlevel of whey proteins and does not exhibit the soft texture andoff-flavor defects commonly associated with the presence of wheyproteins in cheese. Moreover, due to the retention of substantially allof the fat and a portion of the whey protein, the filtration andoptional evaporation steps may yield a high solids content product, andthus the compositions subjected to filtration and evaporation may notrequire fat correction. Further, by reserving cream for UF, fouling ofthe MF system by cream is avoided.

Implementations of the present disclosure provide several benefits overprior approaches. As described herein, the MF product having serumproteins removed may not exhibit the soft texture and off-flavorcommonly associated with the presence of certain proteins in cheese. Inaddition, the addition of cream to the MF retentate before UF allows forfurther removal of moisture from the MF retentate. Further, UF followingthe combination of cream with the MF retentate may enable lactoseremoval from cream, which may yield a product with a lower lactosecontent. Further still, in certain implementations, the combination ofsalt and lactic acid to the UF/DF retentate may facilitate furthermoisture removal during evaporation. In-line addition of salt andacidification before shearing may reduce processing time and loweroperational cost. Shearing the UF/DF retentate after acidification andthe addition of salt may additionally facilitate reduced productiontimes because the sheared UF/DF acidified and salted retentate has areduced gel pH and ionic strength buffer capability and increaseddiffusion rate, which makes the intermediate product ready for cooking,for example, in a cooker. In additional or alternative implementations,the use of shearing, the addition of salt and acidification allow for amore homogenous material to be fed to the evaporator.

In implementations of use, the food product of the present disclosuremay be natural, process or enzyme modified cheeses and may be used inflavored cheese powders, process cheese products, as a dairy base forhigh protein puddings, and so on.

In another exemplary embodiment, and with reference to the method 500 ofFIG. 5, whole milk may be heat-treated to about 140° F. at step 510prior to separation of the whole milk into cream and skim milk at step520. During separation, the skim milk stream outlet may have a pressureof about 70 PSI while the cream outlet may have a pressure of about 102PSI (while adjusting back pressure). The separation ratio of cream vs.skim milk by weight may be about 9%, i.e., about 9% wt % of the wholemilk is separated into cream, while about 91% wt % of the whole milk isseparated into skim milk. Separation may occur at temperatures of about130° F. to about 140° F. The separated skim milk and cream may betransferred in a continuous manner for further processing, e.g., duringcontinuous production, or can be reserved, such as for batch operations.In batch operations, the skim milk and/or cream may be stored and cooledto temperatures below 40° F., e.g., about 35° F. to 40° F. Exemplarycompositions of cream, skim milk, MF retentate, MF retentate and cream(Blend), and UF retentate streams that may be produced according tomethod 500 are provided in Table 1.

TABLE 1 Composition of streams in method 500 Composition, Skim MFR/CreamFood wt % Cream milk MFR Blend UFR Product Total solid 50 9.19 10.3 16.941.6 65.0 Non-protein 0.1 0.18 0.14 0.1 N/A N/A Nitrogen Total protein1.93 3.41 7.2 6.14 14.2 22.2 Casein 1.48 2.62 6.6 5.38 12.4 19.4 Serumprotein 0.36 0.61 0.51 0.66 1.8 2.8 Lactose 2.57 4.82 1.87 1.67 0.530.80 Ash N/A 0.75 0.88 0.74 1.4 2.2 Fat 45 0.05 0.15 9.2 25.4 39.7

At step 530, skim milk may be subjected to MF and optionally DF. Themembranes used in step 530 may be ceramic or polymeric and may have apore size ranging from about 0.05 μm to 0.5 μm, although a ceramicmembrane with a pore size of about 0.1 μm may be preferred. Variationsin the membrane material and the membrane pore size alter the level oftransmission of serum protein through the membrane. A larger pore sizeceramic membrane has a much greater serum protein transmission comparedto a smaller pore size polymeric membrane. Step 530 may proceedaccording to a batch or continuous process. When used as a batchprocess, step 530 may reduce the final concentrated volume of the skimmilk to about 50 down to about 25 percent of the original volume of theskim milk, or preferably about 33 percent of the original volume. Usinga continuous process, the ratio of flow rate of permeate vs. retentatemay be controlled and may range from about 1 to 3, and in some preferredimplementations the ratio may be 2. An exemplary MF/DF retentatecomposition using three cycles of MF/DF in a batch process using 0.1 μmceramic membrane is presented in Table 1 (MFR). Additionally, the volumeof water used in DF also affects the recovery of serum protein,resulting in different concentrations of serum protein in the permeate.For instance, the serum protein concentration in a MF retentate after athree cycles of MF/DF can range from about 0.2 to 2.0 wt %. Step 530 maybe conducted at temperatures at about 120° F. to about 130° F.

At step 540, cream may be added back to the MF retentate and the blendsubjected to UF and optionally DF. For instance, cream may be added toreach a blend with a fat-to-casein-protein ratio of 1.71 and the blendmay be concentrated using a UF process. For instance, UF may use amembrane molecular weight cut-off around 10 k Dalton. The composition ofan exemplary blend of cream/MF retentate composition is presented inTable 1 (MFR/Cream Blend). Step 540 may be conducted at 120° F. to 130°F. or at 40 to 50° F. The UF retentate may have a total solids contentof about 40 wt %. An exemplary composition of a UF/DF retentate ispresented in Table 1 (UFR). DF may be used to reduce lactose content.

At step 550, the UF retentate may be transferred to a blender orblending tank where salt and/or acid (e.g., lactic acid) may be added.

Acidification of the UF retentate, for instance in step 550, may providea controlled approach to production of a food product (e.g., cheese orcheese base) compared to using cultures, which can provide variabilitydepending on the culture strain(s) used. Particularly, use of directacidification through the addition of acid may eliminate the need forculture strains and therefore the ending food product may be free ofculture(s). This may prevent the accumulation of galactose, which canoccur with some culture strains; and which, in turn, may promoteMaillard browning. Particularly, galactose has more potential as areducing sugar than lactose to promote such a reaction (Zehren &Nusbaum, Process Cheese pages 157 & 270). Acid addition after UFadditionally preserves all of the acid in the food product as opposed toacid loss in permeate during filtration. Acidification after MF/DFprevents the aggregation of serum protein with divalent cations, such ascalcium, in the MF permeate. If lactic acid is added before MF/DF, incontrast, calcium and phosphorous, released from casein micelle due tothe pH reduction, can pass through MF membrane and accumulate in thepermeate. Acidification after MF/DF thus results in more dairy mineralsbeing retained in the retentate stream. Further, acidification after MFand UF avoids localized coagulation of casein in the MF and UF retentatestreams and the subsequent precipitation of this coagulated casein onthe membrane surfaces. Otherwise, precipitation of casein on themembrane surfaces causes reduced membrane performance and makes it moredifficult to clean the membranes.

Other food grade acids such as phosphoric acid or monosodium phosphatemay be used to acidify the UF retentate in step 550. For instance,adding monosodium phosphate prior to lactic acid addition may stabilizethe mixture prior to evaporation and may thus prevent the compositionfrom curdling and may eliminate the need for a homogenization step.

At step 560, the composition may be subjected to shear to reachequilibrium through homogenization, for instance, using a shear pump.Shearing breaks apart fat globules and distributes fat throughout thedairy system to provide smoothness and increased viscosity to thecomposition.

Optional evaporation step 570 may remove moisture and raise the totalsolids content, for instance, to about 65 wt % total solids. In certainimplementations, the addition of salt and acid may enable theevaporation step 570 to reach a higher solids level in the productexiting an evaporator. Because a portion of the whey proteins areremoved during MF of the skim milk, the UF retentate may be subjected tothe evaporation step 570 at higher temperatures, for instance, toincrease the solids content of the final product at a higher rate, or tofeed the UF retentate at a faster rate to achieve the same percentsolids in the final product to thereby produce more final product perunit of time. Particularly, whey protein is more heat sensitive comparedto casein, and when higher levels of whey protein are present (e.g.,when skim milk is not subjected to MF), the risk of denaturation of thewhey protein and subsequent cross-linking of the whey protein to yield anon-meltable product is elevated when evaporation is conducted at highertemperatures. Because the ratio of casein is relatively higher in theprotein fraction of the UF retentate, and because casein is more heatstable and does not cross-link in the same manner as whey protein, moreof the UF protein content remains intact at elevated temperaturesenabling a higher solids content or increased production level.

Following step 560 or optionally evaporation step 570, the compositionmay be further processed, for instance, by sending the composition to afilling station 170, a barrel filling system 180, a cooker 220 and/or afiller 230. In addition or alternatively, optional additives such ascultures, enzymes and/or emulsifiers may be added to the composition.

The food product produced after UF, or after the optional evaporation instep 570, may contain a total solids content of about 45 to 80 wt %,preferably about 62 to 67 wt % and most preferably about 65 wt %. On adry basis, fat in the food product may be present at about 25 to 65 wt%, preferably at about 50 to 56 wt % and most preferably about 53 wt %.Serum protein present in the food product may be about 0.9 to 6.0 wt %,preferably about 1.5 to 2.0 wt %, and more preferably about 1.60 to 1.80wt %.

The steps described in systems and methods 100-500 may proceed in anyorder or combination. For instance, the addition of lactic acid in step550 may follow the evaporation step 570. Addition of lactic acidfollowing evaporation may modify the texture of the food product, andparticularly may yield a softer material for use in later productionsteps.

The steps described in systems and methods 100-500 may additionally bedivided into substeps or only portions of steps may be performed. Forinstance, adding lactic acid before salt in step 550, prior toevaporation in step 570, or with no salt at all prior to evaporation,may accelerate moisture loss by the casein through the evaporationprocess. When no salt is added in step 550, less lactic acid may be usedin the process than if salt had been added as protein may be lesssolvated with moisture where the salt is not present, thereby avoidinghydration of the protein with moisture and subsequent shielding of theprotein from the hydrogen ions present from the acid source.

Moreover, the steps described in systems and methods 100-500 may berepeated. For instance, one or more MF steps 530 may proceed undertemperature conditions of 120° F. to 130° F. as described to remove whey(serum proteins) and another MF step 530 may proceed using coldertemperatures such as about 40° F. to 60° F. These secondary MF in step530 may precede combining cream with the MF retentate in the UF step540. In addition to performing MF at cold temperatures, the MF retentateinitially formed may be stored at lower temperatures, e.g., at about 40°F., for a period of time such as about twelve or more hours prior tocold temperature MF. During cold temperature storage, beta casein maydissociate from the casein micelle and subsequent cold temperature MF,e.g., at about 40° F. to 60° F., may result in the MF permeatecontaining the dissociated beta casein. For instance, a polymeric MFmembrane with a pore size 0.5 μm may result in the MF permeatecontaining the beta casein. The beta casein in the secondary MF permeatemay be relatively pure because the initial MF results in removal of theserum proteins, i.e., the initial permeate contains permeable proteins.As a result, the secondary permeate containing primarily beta casein maybe heated up and then combined with a different stream of skim or MFretentate or used as diafiltration medium to process MF/DF undertemperature conditions of 120° F. to 130° F., thus having the effect ofaltering the beta casein fraction in the total casein of the MF/DFretentate and finished concentrate.

Further, the steps described in systems and methods 100-500 may includeadditional steps. For instance, the UF retentate may optionally beconstantly circulated in a step 545 following step 540. Constantcirculation of the UF retentate with added salt, before or after theaddition of lactic acid and other additives (e.g., water, fat, protein(e.g., MF retentate), starch, gums, flavorings), may prevent the UFretentate from gelation. In particular, UF retentate in its native stateis prone to a phenomenon known as age gelation due to a relatively highconcentration of micellar casein. In age gelation, micellar caseindisassociates from the casein micelle upon the nucleation of calciumphosphate within the system. Calcium phosphate nucleation will occurover time as it is less stable thermodynamically in the native caseinmicelle. Casein disassociation from the micelle leads to cross-linkingbetween the casein sub-particles and calcium phosphate complexes,causing gel formation to occur within the system (Van Dijk, H. J. M.,The properties of casein micelles-Changes in the state of the micellarcalcium phosphate and their effects on other changes in the caseinmicelles, 44 Netherlands Milk and Dairy Journal, 125-141 (1990)). Thisreaction is further catalyzed by higher temperatures. It has beendiscovered that constant circulation of the UF retentate with about 1 wt% added salt prevents age gelation and allows the UF retentate tomaintain a viscosity at or below about 1000 cP for at least 8 hours andup to 48 hours. By providing a UF retentate adapted to maintain a lowviscosity, food products formed of the UF retentate may be stored in anenvironment prior to being transferred for use in final productionsteps. This allows the UF retentate to be maintained in its native,non-homogenized state or substantially native state (e.g., with one ormore additives) for at least about 8 and up to about 48 hours until theUF retentate is used in final production steps such, as but not limitedto, mixing, cooking, homogenization, entering a stuffer, or filling(e.g., barrel filling).

Constant circulation of the UF retentate in step 545 to maintain aviscosity at or below about 1000 cP may involve using one or more ofpumping or sweeping as described further in connection with Example 1.Pumping is generally by use of a positive displacement pump thatcirculates the UF retentate. Sweeping may involve the use of a spindleor other device in a vessel that runs at a low speed (e.g., 2 to 10rpms) to maintain slight circulation of the UF retentate. Thecirculation step may proceed at temperatures of about 120° F. to 160°F., preferably about 130° F. to 150° F., and more preferably at about140° F.

Step 545 may optionally follow the step 550 such that the UF retentateis combined with one or more additives such as salt, lactic acid, water,fat, protein (MF retentate) and/or sugar in is constantly circulated tomaintain the viscosity of the composition below about 1000 cP. Forinstance, a portion of the MF retentate produced in step 530 may bereserved so that it is not subjected to UF with the cream, and then thereserved MF retentate may be added to the UF retentate in step 550 toincrease moisture and protein and constantly circulated in step 545. Ina particular example, the MF retentate may contain about 10 to 12 wt %total solids, with about 75 percent of the total solids formed ofprotein (i.e., about 7.5 to 9 wt % of MF retentate). Thus the additionof the MF retentate to the UF retentate, increases protein and moisture.

Following the optional constant circulation step 545, the compositionmay be subjected to shear in step 560, such as homogenization, to reacha selected viscosity as described further in connection with Example 2.

Example 1

This example investigates whether pumping, sweeping or holding UFretentate at higher temperatures (approximately 140° F.) can inhibit agegelation for at least 48 hours.

Materials and Methods

UF retentate samples produced according to the preceding methods weresalted at levels of about 1.05 wt %, 1.14 wt %, and 1.22 wt % andpasteurized (165° F. for 1 minute) in a double boiler on a stove top. Anunsalted UF retentate was used as the control. The UF retentatecontained 57 wt % moisture, 43 wt % solids, 14 wt % protein in the formof casein and some whey, 0.7 wt % lactose and 26.5 wt % fat. Initialmoisture (CEM), water activity, pH, and viscosity readings were taken.Viscosity was measured on a Brookfield viscometer with a number 72 vanespindle set to 5 rpms. After the 48 hour hold, moisture and wateractivity were measured again.

Pump Study:

The UF retentate samples were then placed into 2, 1000 mL stainlesssteel beakers in a water bath set to 140° F. Plastic tubing attached toa positive displacement pump was then placed into the beakers and sealedwith a rubber gasket to allow for circulation of the UF retentate at ahigh temperature with minimal moisture loss. All samples were mixed byhand with a spoon prior to viscosity testing. Viscosity and pH readingswere taken at two hour increments up to 48 hours of holding time.

Viscosity Sweep:

Pasteurized UF retentate control (no salt) and salted to 1.05 wt %samples were placed in a 1000 mL beaker in a water bath set to 140° F. Anumber 72 vane spindle attached to a Brookfield DVT3 rheometer was thenplaced into the beakers and run at 5 rpms. Viscosity readings wererecorded every minute for 48 hours. The beakers were sealed with arubber gasket to prevent moisture loss.

Holding Test:

Pasteurized UF retentate samples salted to 1.05%, 1.14%, and 1.22% and acontrol (no salt or acid and no salt) were placed in 400 mL beakers in awater bath set to 140° F. and held for 48 hours. Viscosity and pHreadings were taken at two hour increments for 48 hours. Viscosity wasmeasured on a Brookfield viscometer with a number 72 vane spindle set to5 rpms. All samples were mixed by hand with a spoon prior to viscositytesting.

Results

Pump Study:

Viscosity results of salted UF retentate samples showed consistentreadings throughout the entire 48 hour pumping cycle. The 1.22 wt % saltUF retentate sample did show some thickening at 48 hours compared tocontrol, while the 1.05 wt % and 1.14 wt % salted UF retentate samplesshowed some thinning at 48 hours compared to initial (FIG. 6). However,all the viscosity readings for all three salted UF retentate sampleswere well within an acceptable process range of the pumping system andremained below 1000 cP. The control UF retentate (unsalted) showedconsistent viscosity within the first 6 hours of holding, but had aviscosity failure (too thick to read) at the 24 hour time point.

Viscosity Sweep:

The UF retentate 1.05 wt % salt sample had consistent and stableviscosity readings throughout the first 29 hours of holding of theviscosity sweep test. A steady viscosity increase is observed after 29hours of hold until the 37 hour time point. A steady decrease was thenobserved until the end time point of 48 hours. All viscosity readingsthroughout the entire hold time were likely within the processcapabilities of a normal plant manufacturing liquid holding system asthe viscosity never got above 1000 cP during the hold time.

The UF retentate unsalted (control) sample showed consistent and stableviscosity readings for the first 9 hours of hold. After this point adramatic increase in viscosity is observed until the 18 hour time pointat which a decrease is observed until the 22 hour time point. Thetesting was stopped at this point as there were high amounts of gellingwithin the sample and the viscosity was much higher than the processcapabilities of a normal plant manufacturing liquid holding system.Viscosity results from both the test and control samples are illustratedin the graph of FIG. 7.

Holding Test:

The UF retentate samples used in the holding test showed a higher degreeof viscosity increase compared to the samples used in the pumping test.The salted UF retentate samples remained stable for the first 6 hours ofholding, and had similar viscosity readings to the same samples withinthe pumping test. However, a dramatic increase in viscosity was observedafter 12 hours and viscosity increased above 1000 cP at 24 hours for the1.05 wt % and 1.14 wt % salt samples. The 1.22 wt % salt sample had amuch lower increase and was within the viscosity range of the resultsfrom the pumping study. Large precipitated particles were also observedwithin these samples at this time point, most notably in the 1.05 wt %and 1.14 wt % salt samples. The viscosity remained stable for the next 6hours of hold after 24 hours for the 1.05 wt % and 1.14 wt % saltsamples while the 1.22 wt % salt sample had a decrease in viscosity andreturned to similar levels observed within the first 6 hours of hold.However, failure was found for all salt samples at the 48 hour mark. Theunsalted control UF retentate sample without lactic acid remained stablefor the first 6 hours of hold, but had a failure at 24 hours.

Conclusions

The results of Example 1 show that in general, the addition of salt toUF retentate is needed for texture stability when holding at 140° F. forextended periods of time equal to or exceeding 8 hours. Unsalted UFretentate became unstable (gelled) within 8 hours for some methods, andwithin 24 hours of holding at 140° F. in all test methods. Whencomparing the results between the pump test and hold test, it appears asthough circulation/agitation also plays a role in maintaining UFretentate texture stability. The viscosity results from the pump testwere relatively consistent throughout the hold and did not exceed 1000cP, while the hold test results showed a higher degree of thickening at24 and 48 hour hold time points for all samples and multiple viscositiesreadings well above 1000 cP. The constant circulation and agitation ofthe UF retentate during the pump study likely kept the micellar caseinwell dispersed within the system, which inhibited cross-liking andcasein aggregation. The viscosity results from the hold test also showthinning and/or stabilization occurring from initial to 6 hour hold timeand from 24 hour to 30 hour hold time. It is likely that repeated handmixing prior to viscosity testing during these time periods dispersedthe casein within the system enough to inhibit or slow caseinaggregation through dispersion and thus prevented thickening. Sincethere was no agitation in the samples for 18 hours prior to the 24 and48 hour time points during the hold test, this is also the likely causefor the large viscosity increases observed at these time points ascasein cross-linking and aggregation was unimpeded by agitation ordispersion. A similar phenomenon also likely occurred in the viscositysweep test, as the vane spindle was constantly turning during the holdtime and thus providing some agitation and dispersion within the sample.

There were no direct trends found between salt content in UF retentateand viscosity between the pumping and hold testing methods. However, the1.14 wt % salt UF retentate sample in the pump test used a pump with ahigher flow rate than the 1.05 wt % and 1.22 wt % samples. The 1.14 wt %salt sample was pumped at a rate of 16 mL/s while the 1.05 wt % and 1.22wt % samples were pumped at a rate of 10.8 mL/s. Therefore, the sampleswere not all subjected to the exact same treatments and may have showndifferent results had the same type of pump been used for all threevariables. It is interesting to note that the 1.22 wt % salt UFretentate was lower in viscosity throughout most of the hold time forboth test methods than the 1.05 wt % salt UF retentate and lower inviscosity than the 1.14 wt % in the hold test. The 1.14 wt % salt UFretentate was also thinner than the 1.05 wt % in both test methods formost of the hold time. It is possible that had the 1.14 wt % salt UFretentate sample used the same type of pump as the other variables, itwould have shown that lower salt content in the UF retentate equates tohigher viscosity and vice versa.

Example 2

This example investigates the effects of homogenization on the viscosityof UF retentate dairy bases having differing moisture, fat and proteinlevels.

Materials, Methods and Results

UF retentate samples produced according to the preceding methodscontained the moisture, fat, and protein values as listed in Table 2.The content of UF retentate used in the formula is also provided inTable 2. Viscosity readings were recorded after processing while at hightemperatures (approximately 140° F.) and again after cooling torefrigeration temperatures (approximately 38-40° F.). The results of theviscosity testing are listed in Table 2.

TABLE 2 Composition targets and viscosity results of UF retentate dairybase UF Moisture Fat Protein retentate Hot Viscosity Cold Viscosity wt %wt % wt % wt % (cP) (140° F.) (cP) (40° F.) 70% 15% 10.5% 55% 0 2800 65%16% 13.0% 59% 3020 66,800 60% 18% 15.0% 68% 20520 128,000 55% 17% 11.0%64% 101,480 601,000

Conclusions

The hot and cold viscosity results of the various homogenized UFretentate dairy bases suggest that homogenization can be used to targeta broad range of end product textures in both hot and cold applications.Without homogenization, the UF retentate would otherwise be grainy andhave no body. The moisture, fat and protein compositional targets forthe UF retentate dairy base as well as the wt % UF retentate within thedairy base contribute to the end product viscosity.

In further exemplary embodiments, a method of forming cheese or cheesebase products involves separation of whole milk into cream and fluidskim followed by MF of the fluid skim to form a MF retentate with serumprotein permeate removed. Cream is added to the MF retentate, and thecream and MF retentate are subjected to UF to form a UF retentate withmoisture removed. Acidification of the UF retentate may result in thecheese/cheese base product.

In some exemplary embodiments, the fluid skim, MF retentate, or UFretentate is subjected to DF to remove lactose.

In addition or alternatively, the whole milk may be separated into fluidskim and cream by a centrifuge.

In addition or alternatively, the UF retentate may be processed toadjust pH by the addition of one or more acids, such as an edible acid.Edible acids may include lactic acid and citric acid.

In addition or alternatively, the UF retentate may be mixed with cheesemaking components such as salt, dairy powders, milk fat, enzymes, andcultures. One or more of these components may be added to the UFretentate in a blending tank, a shear pump, and/or a blender. In someimplementations, mixture of the salt and acid may be in one or moreblending tanks. In some implementations, homogenization of the mixturemay be via the shear pump. In some implementations, cultures, enzymes,dairy powders, milk fat and water may be added prior to or duringaddition of the UF retentate to a blender.

In addition or alternatively, the UF retentate may be processed throughevaporation to adjust moisture content. Evaporation may be conductedusing a wiped film evaporator (e.g., turba fan evaporator), a thin filmevaporator, a scraped surface heat exchanger, and so on. In someimplementations a wiped film evaporator may be preferred.

In addition or alternatively, the UF retentate or a mixture of the UFretentate and one or more cheese components may be cooked in a cheesecooker.

In addition or alternatively, the UF retentate, a mixture of the UFretentate, and/or a cooked mixture may be provided to a stuffer, to afiller, to a metal detector, or to another system for production andpackaging of cheese.

While the methods disclosed herein have been described and shown withreference to particular operations performed in a particular order, itwill be understood that these operations may be combined, sub-divided,or re-ordered to form equivalent methods without departing from theteachings of the present disclosure. Accordingly, unless specificallyindicated herein, the order and grouping of the operations should not beconstrued as limiting.

Similarly, it should be appreciated that in the foregoing description ofexample embodiments, various features are sometimes grouped together ina single embodiment, figure, or description thereof for the purpose ofstreamlining the disclosure and aiding in the understanding of one ormore of the various aspects. These methods of disclosure, however, arenot to be interpreted as reflecting an intention that the claims requiremore features than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive aspects lie in less than allfeatures of a single foregoing disclosed embodiment, and each embodimentdescribed herein may contain more than one inventive feature.

While the present disclosure has been particularly shown and describedwith reference to embodiments thereof, it will be understood by thoseskilled in the art that various other changes in the form and detailsmay be made without departing from the spirit and scope of thedisclosure.

What is claimed is:
 1. A method for the production of a food product,the method comprising: subjecting skim milk to microfiltration (“MF”) toremove at least a portion of whey protein thereby forming a skim milk MFretentate; combining cream with the skim milk MF retentate; subjectingthe combined cream and skim milk MF retentate to ultrafiltration (“UF”)to remove moisture and increase total solids thereby forming a UFretentate, wherein the UF retentate contains at least about 1 wt % salt;and maintaining a viscosity of the UF retentate below 1000 cP for atleast about 8 hours.
 2. The method of claim 1, wherein the step ofmaintaining a viscosity of the UF retentate below 1000 cP is bycirculating the UF retentate using one or more of pumping or sweeping.3. The method of claim 2, wherein circulating the UF retentate isperformed at a temperature of about 120° F. to about 160° F.
 4. Themethod of claim 1, wherein after the step of maintaining, furthercomprising adjusting the viscosity of the UF retentate to a selectedviscosity.
 5. The method of claim 4, wherein the step of adjusting is byhomogenization.
 6. The method of claim 4, wherein after the step ofadjusting the viscosity of the UF retentate, further comprisingsubjecting the UF retentate to evaporation.
 7. The method of claim 6,further comprising elevating a temperature of the UF retentate duringevaporation.
 8. The method of claim 1, further comprising: reserving aportion of the MF retentate prior to the step of combining; and addingthe reserved portion of the MF retentate to the UF retentate, therebyincreasing moisture and protein in the UF retentate.
 9. The method ofclaim 1, wherein prior to the step of subjecting to UF, the combinationof the cream and the skim milk MF retentate is non-acidified.
 10. Themethod of claim 1, further comprising, prior to the step of combining,subjecting the MF retentate to a second MF at a second temperaturedifferent from the first, and wherein the second MF removes beta casein.11. The method of claim 1, wherein, prior to the step of combining, theMF retentate is cooled to a temperature of about 40° F. to 60° F. andsubjected to MF.
 12. The method of claim 11, wherein the MF retentate iscooled to a temperature of about 40° F. to 60° F. for at least about 12hours.
 13. The method of claim 1, wherein the MF retentate comprisesabout 10 wt % to about 12 wt % total solids.
 14. The method of claim 1,wherein the MF retentate comprises about 7.5 wt % to about 9 wt %protein.
 15. The method of claim 1, wherein the viscosity of the UFretentate is maintained below 1000 cP for between about 8 hours andabout 48 hours.
 16. The method of claim 1, wherein the UF retentatecomprises about 45 wt % to about 80 wt % total solids.